Patchouli oil, usually obtained by steam distillation of the dried leaves of Pogostenum Patchouli Pellet, a small plant of the family of labiates, is a very important perfume material. Owing to its property of easily and harmoniously blending with a great variety of different perfuming coingredients, Patchouli oil is used extensively in a wide range of fragrance compositions.
As a consequence, it is not astonishing to observe an ever increasing interest in the study of its composition, precisely in view of achieving its faithful reconstitution. Several cyclic sesquiterpenes have been identified among the constituents isolated sofar from pathouli oil. These derivatives include 4,8,11,11-tetramethyltricyclo [5.3.1.0.sup.3,8 ] undecan-7-ol, better known under the name of patchoulol, which compound, as main constituent, plays a major role in the oil reconstitution. Patchoulol, which was first isolated already in 1869 by H. Galin [vide: C. Rend.Aca. Sci., 63, 406 (1869)] can be synthetized according to several known methods. These include those namely described by G. Buchi et al. [J. Am Chem. Soc., 83, 927 (1961); idem, 86, 4438 (1964)], S. Denishetski and D. Dumas [Chem. Comm., 1968 1287] and M. Mirrington and K. J. Schmalzl [J. Org. Chem. 37, 2871 (1972)]. These preparations possess an undeniable academic interest, however they suffer from serious disadvantages whenever it is desired to apply them to large scale industrial preparations, as the required starting materials are not commercially available and their preparation requires lengthy multistep synthetic processes.